Symbols in old books stored in country (8)
I believe the answer is:
notation
'symbols' is the definition.
(I've seen this before)
'old books stored in country' is the wordplay.
'old books' becomes 'ot' (Old Testament).
'stored in' is an insertion indicator.
'country' becomes 'nation' ('nation' can be a synonym of 'country').
'ot' inserted within 'nation' is 'NOTATION'.
'in' is the link.
(Other definitions for notation that I've seen before include "Set of symbols representing quantity etc." , "A comment added to a text" , "System of written symbols representing something" , "An added comment or instruction" , "System of musical symbols" .)